scholarly journals Ecological performance differs between range centre and trailing edge populations of a cold-water kelp: implications for estimating net primary productivity

2020 ◽  
Vol 167 (9) ◽  
Author(s):  
Nathan G. King ◽  
Pippa J. Moore ◽  
Albert Pessarrodona ◽  
Michael T. Burrows ◽  
Joanne Porter ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Primary Productivity ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Cold Water ◽  
Standing Stock ◽  
Kelp Forests ◽  
Growth Season ◽  
Trailing Edge ◽  
Carbon Cycles

Abstract Kelp forests are extensive, widely distributed and highly productive. However, despite their importance, reliable estimates of net primary productivity (NPP) are currently unknown for most species and regions. In particular, how performance and subsequent NPP change throughout a species range is lacking. Here, we attempted to resolve this by examining growth and performance of the boreal kelp, Laminaria digitata, from range centre and trailing edge regions in the United Kingdom. During the peak growth season (March/April), range-centre individuals were up to three times heavier and accumulated biomass twice as fast as their trailing-edge counterparts. This was not apparent during the reduced growth season (August/September), when populations within both regions had similar biomass profiles. In total, annual NPP estimates were considerably lower for trailing-edge (181 ± 34 g C m−2 year−1) compared to range-centre (344 ± 33 g C m−2 year−1) populations. Our first-order UK estimates of total standing stock and NPP for L. digitata suggest this species makes a significant contribution to coastal carbon cycling. Further work determining the ultimate fate of this organic matter is needed to understand the overall contribution of kelp populations to regional and global carbon cycles. Nevertheless, we highlight the need for large-scale sampling across multiple populations and latitudes to accurately evaluate kelp species’ contributions to coastal carbon cycling.

scholarly journals More individuals but fewer species: testing the ‘more individuals hypothesis’ in a diverse tropical fauna

2010 ◽  
Vol 6 (4) ◽  
pp. 490-493 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Michael D. Weiser ◽  
Robert R. Dunn
Keyword(s):  
Species Richness ◽  
Primary Productivity ◽  
Large Scale ◽  
Positive Relationship ◽  
Tropical Rainforest ◽  
Net Primary Productivity ◽  
Resource Abundance ◽  
Monotonic Increase ◽  
Ant Diversity ◽  
Unimodal Relationship

A positive relationship between species richness and productivity is often observed in nature, but the causes remain contentious. One mechanism, the ‘more individuals hypothesis’ (MIH), predicts richness increases monotonically with density, as a function of resource flux. To test the MIH, we manipulated resource abundance in a community of tropical rainforest litter ants and measured richness and density responses. A unimodal relationship between richness and density most closely fitted the control and disturbance (resource removal) treatments in contrast to expectations of the MIH. Resource addition resulted in a monotonic increase in richness relative to density, a shift from the pattern in the control. In the disturbance treatment, richness was greater than in the control, opposite to expectations of the MIH. While large-scale correlations between ant diversity and net primary productivity or temperature are reconcilable with the MIH, key elements of the hypothesis are not supported.

scholarly journals The up-scaling of ecosystem functions in a heterogeneous world

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Andrew M. Lohrer ◽  
Simon F. Thrush ◽  
Judi E. Hewitt ◽  
Casper Kraan
Keyword(s):  
Primary Productivity ◽  
Ecosystem Functioning ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Marine Ecosystem ◽  
Ecosystem Functions ◽  
Small Scale ◽  
Biodiversity Crisis ◽  
Positive Effects ◽  
Marine Habitats

Abstract Earth is in the midst of a biodiversity crisis that is impacting the functioning of ecosystems and the delivery of valued goods and services. However, the implications of large scale species losses are often inferred from small scale ecosystem functioning experiments with little knowledge of how the dominant drivers of functioning shift across scales. Here, by integrating observational and manipulative experimental field data, we reveal scale-dependent influences on primary productivity in shallow marine habitats, thus demonstrating the scalability of complex ecological relationships contributing to coastal marine ecosystem functioning. Positive effects of key consumers (burrowing urchins, Echinocardium cordatum) on seafloor net primary productivity (NPP) elucidated by short-term, single-site experiments persisted across multiple sites and years. Additional experimentation illustrated how these effects amplified over time, resulting in greater primary producer biomass (sediment chlorophyll a content) in the longer term, depending on climatic context and habitat factors affecting the strengths of mutually reinforcing feedbacks. The remarkable coherence of results from small and large scales is evidence of real-world ecosystem function scalability and ecological self-organisation. This discovery provides greater insights into the range of responses to broad-scale anthropogenic stressors in naturally heterogeneous environmental settings.

scholarly journals Characteristics of aquatic biospheres on temperate planets around Sun-like stars and M dwarfs

2021 ◽  
Vol 503 (3) ◽  
pp. 3434-3448
Author(s):  
Manasvi Lingam ◽  
Abraham Loeb
Keyword(s):  
Primary Productivity ◽  
Large Scale ◽  
Carbon Fixation ◽  
Net Primary Productivity ◽  
Effective Rate ◽  
Environmental Variable ◽  
Oxygenic Photosynthesis ◽  
M Dwarfs ◽  
Earth Like Planets ◽  
Rocky Planets

ABSTRACT Aquatic biospheres reliant on oxygenic photosynthesis are expected to play an important role on Earth-like planets endowed with large-scale oceans insofar as carbon fixation (i.e. biosynthesis of organic compounds) is concerned. We investigate the properties of aquatic biospheres comprising Earth-like biota for habitable rocky planets orbiting Sun-like stars and late-type M dwarfs such as TRAPPIST-1. In particular, we estimate how these characteristics evolve with the available flux of photosynthetically active radiation (PAR) and the ambient ocean temperature (TW), the latter of which constitutes a key environmental variable. We show that many salient properties, such as the depth of the photosynthesis zone and the net primary productivity (i.e. the effective rate of carbon fixation), are sensitive to PAR flux and TW and decline substantially when the former is decreased or the latter is increased. We conclude by exploring the implications of our analysis for exoplanets around Sun-like stars and M dwarfs.

scholarly journals Description and Validation of the Simple, Efficient, Dynamic, Global, Ecological Simulator (SEDGES v.1.0)

2017 ◽  
Author(s):  
Pablo Paiewonsky ◽  
Oliver Elison Timm
Keyword(s):  
Primary Productivity ◽  
Land Surface ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Bare Soil ◽  
Relative Advantage ◽  
Coupling Scheme ◽  
Area Index

Abstract. In this paper, we present a simple vegetation model whose primary intended use is auxiliary to the land-atmosphere coupling scheme of a climate model, particularly one of intermediate complexity. The model formulations and their derivations are presented here, in detail. The model includes some realistic and useful features for its level of complexity, including a photosynthetic dependency on light, full coupling of photosynthesis and transpiration through an interactive canopy resistance, and a soil organic carbon dependence for bare soil albedo. We evaluate the model's performance by running it using a simple land surface scheme that is driven by reanalysis data. The evaluation against observational data includes net primary productivity, leaf area index, surface albedo, and diagnosed variables relevant for the closure of the hydrological cycle. In this set up, we find that the model gives an adequate to good simulation of basic large-scale ecological and hydrological variables. Of the variables analyzed in this paper, gross primary productivity is particularly well simulated. The results also reveal the current limitations of the model. The most significant deficiency is the excessive simulation of evapotranspiration in mid- to high northern latitudes during their winter to spring transition. The model has relative advantage in situations that require some combination of computational efficiency, model transparency and tractability, and the simulation of the large scale vegetation and land surface characteristics under non-present day conditions.

scholarly journals Spatio-Temporal Evolution, Future Trend and Phenology Regularity of Net Primary Productivity of Forests in Northeast China

2020 ◽  
Vol 12 (21) ◽  
pp. 3670
Author(s):  
Chunli Wang ◽  
Qun’ou Jiang ◽  
Xiangzheng Deng ◽  
Kexin Lv ◽  
Zhonghui Zhang
Keyword(s):  
Sustainable Development ◽  
Primary Productivity ◽  
Northeast China ◽  
Net Primary Productivity ◽  
Temporal Evolution ◽  
Significant Advance ◽  
Reverse Direction ◽  
Growth Season ◽  
Vegetation Growth ◽  
Spatio Temporal

Net Primary Productivity (NPP) is one of the significant indicators to measure environmental changes; thus, the relevant study of NPP in Northeast China, Asia, is essential to climate changes and ecological sustainable development. Based on the Global Production Efficiency (GLO-PEM) model, this study firstly estimated the NPP in Northeast China, from 2001 to 2019, and then analyzed its spatio-temporal evolution, future changing trend and phenology regularity. Over the years, the NPP of different forests type in Northeast China showed a gradual increasing trend. Compared with other different time stages, the high-value NPP (700–1300 gC·m−2·a−1) in Changbai Mountain, from 2017 to 2019, is more widely distributed. For instance, the NPP has an increasing rate of 6.92% compared to the stage of 2011–2015. Additionally, there was a significant advance at the start of the vegetation growth season (SOS), and a lag at the end of the vegetation growth season (EOS), from 2001 to 2019. Thus, the whole growth period of forests in Northeast China became prolonged with the change of phenology. Moreover, analysis on the sustainability of NPP in the future indicates that the reverse direction feature of NPP change will be slightly stronger than the co-directional feature, meaning that about 30.68% of the study area will switch from improvement to degradation. To conclude, these above studies could provide an important reference for the sustainable development of forests in Northeast China.

A CLASSIFICATION INDICES-BASED MODEL FOR NET PRIMARY PRODUCTIVITY (NPP) AND POTENTIAL PRODUCTIVITY OF VEGETATION IN CHINA

2012 ◽  
Vol 05 (03) ◽  
pp. 1260009 ◽  
Author(s):  
HUILONG LIN ◽  
JUN ZHAO ◽  
TIANGANG LIANG ◽  
JAN BOGAERT ◽  
ZHENQING LI
Keyword(s):  
Primary Productivity ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Global Climate ◽  
Terrestrial Ecosystem ◽  
Terrestrial Vegetation ◽  
Moisture Index ◽  
Potential Productivity ◽  
Climate Conditions ◽  
Factors Affecting

Net Primary Productivity (NPP) is an important parameter, which is closely connected with global climate change, the global carbon balance and cycle. The study of climate-vegetation interaction is the basis for research on the responses of terrestrial ecosystem to global change and mainly comprises two important components: climate vegetation classification and the NPP of the natural vegetation. Comparing NPP estimated from the classification indices-based model with NPP derived from measurements at 3767 sites in China indicated that the classification indices-based model was capable of estimating large scale NPP. Annual cumulative temperature above 0°C and a moisture index, two main factors affecting NPP, were spatially plotted with the ArcGIS grid tool based on measured data in 2348 meteorological stations from 1961 to 2006. The distribution of NPP for potential vegetation classes under present climate conditions was simulated by the classification indices-based model. The model estimated the total NPP of potential terrestrial vegetation of China to fluctuate between 1.93 and 4.54 Pg C year-1. It provides a reliable means for scaling-up from site to regional scales, and the findings could potentially favor China's position in reducing global warming gases as outlined in the Kyoto Protocol in order to fulfill China's commitment of reducing greenhouse gases.

scholarly journals Above-ground net primary productivity in young stands of beech and spruce

2013 ◽  
Vol 59 (3) ◽  
Author(s):  
Jozef Pajtík ◽  
Bohdan Konôpka ◽  
Róbert Marušák
Keyword(s):  
Climate Change ◽  
Primary Productivity ◽  
Tree Species ◽  
Net Primary Productivity ◽  
Standing Stock ◽  
European Beech ◽  
Forest Tree ◽  
Tree Species Composition ◽  
Climate Conditions ◽  
Resistant Species

AbstractOne of the expected consequences of climate change and its inherent phenomena to forest ecosystems is the gradual modification of their tree species composition (i.e. expansion of resistant species instead of less resistant ones). Climate change accompanied with increasing temperatures and a lack of precipitations may present a threat especially to spruce stands in the European part of the temperate zone. European beech is one of the possible forest tree species which might replace the potentially endangered spruce. In this paper, we observed, by using a combination of continual measurements and destructive whole-tree sampling, standing stocks of above-ground biomass (i.e. stem, branches, and foliage) and its annual net primary productivity (NPP) in naturally regenerated young stands of beech and spruce. We intentionally selected a site where the changing climate conditions are better suited to the ecological demands of beech rather than spruce (the species is dominant in the observed area). We recorded only small differences in the standing stock of stems of the beech, if based on tons per ha. However, this is in favor of spruce if based on cubic meters per ha. The largest difference between the species was found for the standing stock of foliage, spruce retained three times the biomass of beech. Also, beech allocated more carbohydrates to stem than spruce. On the other hand, we estimated nearly the same production of foliages and branches in both stands.

scholarly journals Description and validation of the Simple, Efficient, Dynamic, Global, Ecological Simulator (SEDGES v.1.0)

2018 ◽  
Vol 11 (3) ◽  
pp. 861-901
Author(s):  
Pablo Paiewonsky ◽  
Oliver Elison Timm
Keyword(s):  
Primary Productivity ◽  
Land Surface ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Relative Advantage ◽  
Coupling Scheme ◽  
Dynamic Global Vegetation Model ◽  
Area Index

Abstract. In this paper, we present a simple dynamic global vegetation model whose primary intended use is auxiliary to the land–atmosphere coupling scheme of a climate model, particularly one of intermediate complexity. The model simulates and provides important ecological-only variables but also some hydrological and surface energy variables that are typically either simulated by land surface schemes or else used as boundary data input for these schemes. The model formulations and their derivations are presented here, in detail. The model includes some realistic and useful features for its level of complexity, including a photosynthetic dependency on light, full coupling of photosynthesis and transpiration through an interactive canopy resistance, and a soil organic carbon dependence for bare-soil albedo. We evaluate the model's performance by running it as part of a simple land surface scheme that is driven by reanalysis data. The evaluation against observational data includes net primary productivity, leaf area index, surface albedo, and diagnosed variables relevant for the closure of the hydrological cycle. In this setup, we find that the model gives an adequate to good simulation of basic large-scale ecological and hydrological variables. Of the variables analyzed in this paper, gross primary productivity is particularly well simulated. The results also reveal the current limitations of the model. The most significant deficiency is the excessive simulation of evapotranspiration in mid- to high northern latitudes during their winter to spring transition. The model has a relative advantage in situations that require some combination of computational efficiency, model transparency and tractability, and the simulation of the large-scale vegetation and land surface characteristics under non-present-day conditions.

scholarly journals Large-scale shift in the structure of a kelp forest ecosystem co-occurs with an epizootic and marine heatwave

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Meredith L. McPherson ◽  
Dennis J. I. Finger ◽  
Henry F. Houskeeper ◽  
Tom W. Bell ◽  
Mark H. Carr ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Large Scale ◽  
Nutrient Dynamics ◽  
Sea Urchins ◽  
Management Strategies ◽  
Kelp Forest ◽  
Kelp Forests ◽  
Predator Population ◽  
Northern California ◽  
Boundary Current

AbstractClimate change is responsible for increased frequency, intensity, and duration of extreme events, such as marine heatwaves (MHWs). Within eastern boundary current systems, MHWs have profound impacts on temperature-nutrient dynamics that drive primary productivity. Bull kelp (Nereocystis luetkeana) forests, a vital nearshore habitat, experienced unprecedented losses along 350 km of coastline in northern California beginning in 2014 and continuing through 2019. These losses have had devastating consequences to northern California communities, economies, and fisheries. Using a suite of in situ and satellite-derived data, we demonstrate that the abrupt ecosystem shift initiated by a multi-year MHW was preceded by declines in keystone predator population densities. We show strong evidence that northern California kelp forests, while temporally dynamic, were historically resilient to fluctuating environmental conditions, even in the absence of key top predators, but that a series of coupled environmental and biological shifts between 2014 and 2016 resulted in the formation of a persistent, altered ecosystem state with low primary productivity. Based on our findings, we recommend the implementation of ecosystem-based and adaptive management strategies, such as (1) monitoring the status of key ecosystem attributes: kelp distribution and abundance, and densities of sea urchins and their predators, (2) developing management responses to threshold levels of these attributes, and (3) creating quantitative restoration suitability indices for informing kelp restoration efforts.

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